The World's #1 Renewable Energy Network for News, Information, and Companies.
Untitled Document

Google-Funded Geothermal Drilling System Could Reduce Costs

The process for creating geothermal wells is very similar to that used for extracting oil and gas, at least in the initial phases.

A conventional drilling rig with a giant-sized drill bit rotating at variable speeds, depending on the density of the rock, drills into the earth, with water or mud circulating through the well shaft to bring rock cuttings to the surface and keep the drill bit (and the well bore) cool.

The technique changes only in the presence of high-temperature steam reservoirs. Then, the final step of drilling is accomplished with air, under pressure, to prevent drilling mud from clogging the bore and preventing the steam from emerging. The method is very nearly as old as the discovery of oil as a fuel source, and is expensive, time-consuming, dangerous and environmentally hazardous – at least in terms of fossil fuel extraction.

A better method, called “spallation,” which refers to chipping or flaking of stone, involves using jet engines to produce superheated, pressurized air which breaks rock.

This method, previously used to fracture granite and marble for commercial use but effective only in surface or close-to-surface applications, is now being applied to deep-well geothermal drilling, but with water as the medium instead of air.

Not only does the method save money by not using drill bits, which break or wear out, costing crews thousands of dollars and hours of time, but drilling is continuous and considerably faster – 30 feet per hour as compared to traditional drilling’s top speed of 10 feet per hour.

The company at the forefront of this newly repurposed technology, Redwood City, California-based Potter Drilling, says that it intends to use the reinvented process to make drilling geothermal wells cheaper and more environmentally friendly. The technology can also be used, to equal advantage, in carbon sequestration, nuclear waste storage, and mining operations.

Potter has already received funding from Google (Nasdaq:GOOG), the world’s best-known Internet search engine and online advertiser.

For Google, it’s part of an overall investment of more than US$30 million in renewable energy announced in 2008, $10 million of that earmarked for geothermal alone and divided among three geothermal companies/projects: AltaRock Energy, Inc., $6.25 million, including whatever was spent for its now defunct initial geothermal project at the Geysers in California; Potter Drilling, $4 million, in two payments, to develop large scale Enhanced Geothermal Systems, or EGS; and Dallas, Texas-based Southern Methodist University Geothermal Lab, $489,521, to map and evaluate U.S. geothermal energy resources.

More support will come from the U.S. Department of Energy, which has committed US$5 million to Potter’s initial drilling efforts in Raymond, California.

There, in the past year and a half, the company has drilled holes ranging from one to four inches in diameter, 1,000 feet deep, to demonstrate the advantages of its hot-water spallation drilling method, which relies on the fact that rock types do not all expand the same amount when heated, resulting in stress and fracturing, the latter releasing the steam needed to power a geothermal energy system.

Geothermal energy can also be developed from hot water – either liquid already in the ground, or surface water pumped in and heated by hot rock formations – but this form of geothermal typically produces less energy because of the lower temperatures involved. (Water becomes steam because of a material phase change at 100 degrees Celsius, or 212 degrees Fahrenheit).

According to the Geothermal Energy Association, geothermal energy has the smallest land-use footprint of any power generation technology, including both traditional sources like coal and oil, and newer, renewable sources like solar and wind.

It is also more reliable than solar and wind, and can be used for baseload electricity generation; every geothermal energy plant built in the last century is still in production, even though production values may have fallen as a result of poor construction or sealing (as is also the case with the BP Gulf oil disaster), or carbonate clogging.

The single drawback to geothermal energy is the high cost of initial development, but if Potter Drilling has its way, that problem may be solved in the near future, leading to the sort of geothermal energy development that could power seven million American homes in the near term, and potentially almost the entire nation when EGS technology is perfected.

Jeanne Roberts is a freelance writer on environment and sustainability issues. In her previous life, she worked as both a reporter and a communications specialist for a major public utility. Her most recent book, Green Your Home, approaches environmentalism from a consumer’s perspective.

This article was originally published on the media outlet EnergyBoom and was reprinted with permission.

Untitled Document

Get All the Renewable Energy World News Delivered to Your Inbox

Subscribe to Renewable Energy World or email newsletter today at no cost and receive the latest news and information.

 Subscribe Now


Top 10 Clean Energy Trends Driving the Global Clean Energy Revolution

Top 10 Clean Energy Trends Driving the Global Clean Energy Revolution

Geothermal Industry Could Come With $73 Billion Price Tag

Anna Hirtenstein, Bloomberg The geothermal industry may need as much as $73 billion in public financing, almost 10 times current spending levels,...

States Already Seek To Delay Clean Power Plan

Andrew Harris, Bloomberg Fifteen states led by coal-rich West Virginia asked a federal court to stall Obama administration rules intended to c...

Global Renewable Energy Roundup: China, Kenya, Turkey, India Seeking More Renewables

Bloomberg News Editors China is being encouraged by three industry groups to double the nation’s solar-power goal for 2020 to make up for sh...


Canadian Solar Wins Five Solar Power Projects Totaling 185 MW in Brazil

These power projects were won under a 20-year Power Purchase Agreement (PPA) with the B...

$100 Off of 5-day Advanced PV Project Experience. Download a Topic Schedule.

Assemble, ground, energize, and commission a complete grid-tied SolarEdge system from s...

Intersolar AWARD „Solar Projects in India“ – Applications being accepted until September 18

The Intersolar AWARD in the category Solar Projects in India honors projects in the fie...

National Thought Leaders to Present on Today's Clean Energy Issues & Trends During IREC's 3iForum at Solar Power International

"An encore to the standing-room-only sessions the past two years, IREC again brings som...


Washington, DC Bridges the Solar Gap

The District of Columbia has enjoyed 15 years of strong economic growth. But prosperity is spread unevenly across the...

Sell Through Hypothesis

You first learned to hypothesize, or make educated guesses, in grade school science class. Now it’s time to ref...

Cronimet / THEnergy study: In solar for mines size does not always matter - Reducing CAPEX with energy efficiency and load shifting

Munich, September 2015. Mining companies are constantly gaining interest in solar solutions because frequently solar ...

Final Program Now Available for GRC Annual Meeting & GEA Geothermal Energy Expo

GRC Annual Meeting & GEA Geothermal Energy Expo - Final Program from



Volume 18, Issue 4


To register for our free
e-Newsletters, subscribe today:


Tweet the Editors! @jennrunyon



GeoPower & Heat Summit

The GeoPower & Heat Summit is the most commercial event in the geoth...

International Energy and Sustainability Conference 2015

The fourth International Energy and Sustainability Conference will be he...

GRC Workshop at Indonesian International Geothermal Convention & Ex...

The Geothermal Conceptual Model & Well Targeting The Geothermal Me...


Final Program Now Available for GRC Annual Meeting & GEA Geothermal...

GRC Annual Meeting & GEA Geothermal Energy Expo - Final Program f...

GRC Annual Geothermal Photo Contest - View all the Entries

36th Annual Geothermal Photo Contest The Geothermal Resources

Why Electric Utilities Love Geothermal

When it comes time to think about replacing the heating and cooling syst...


Renewable Energy: Subscribe Now

Solar Energy: Subscribe Now

Wind Energy: Subscribe Now

Geothermal Energy: Subscribe Now

Bioenergy: Subscribe Now